Control device



Nov. 24, 1964 H. ALEXANDER 3,158,317

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assignor, by mesne assignments, to The Bunker-flame Corporation, CanogaPark, Calill, a corporation of Maryland Filed July 8, 1963, Ser. No.293,529 20 Claims. (Cl. 235-445) This invention relates generally toelectrical control devices and, more particularly, to a control devicewhich is particularly suited to act as an input/output device for use inconjunction with a digital computer for facilitating communicationbetween a human operator and the computer.

In the use of digital computers for problem analysis, it is usuallyinitially necessary for a requester to present a request to a programmerin order to code the request in such terms as to be compatible with thecomputer. Secondly, it is necessary to operate input equipment capableof generating signals corresponding to the coding, and for these signalsto be entered into the computer. Thereafter, the computer will performthe operations specified by the request and produce output signals whichmay be presented in various forms.

The procedural chain which necessitates the programmer coding therequesters request often makes it impossible to obtain a response in areasonably fast time. Often, total response times dwarf the actual timerequired by the computer, which is usually capable of providingresponses in fraction of a second once the appropriate data has beensupplied to it. In order to lessen total response time, input/outputdevices have been developed which can be electrically tied to thecomputer so as to achieve this purpose for certain specializedapplications. The input/output devices developed to date, however, aregenerally limited to a relatively small number of functions in the dataprocessing and display chain.

Excessive total response times are made even less tolerable by the factthat certain problems are only partially amenable to solution byelectronic data processing. Many problem areas, as, for example,management control, logistics, and air tratlic control, often can betterbe investigated if human intervention is permitted for making certaindecisions during the data processing. The reason for permitting humanintervention is that in some cases, the nature of the data, types ofdecision required and relative importance of various factors are toounpredictable for automatic processing and it is not practical to Writeprograms to cover all possible situations. This is especially true wheresome situations remain unknown until they are actually encountered, andare not capable of being anticipated for inclusion in a program.

Another reason preventing completely automatic handling of certainproblems is the fact that trial and error procedures must often be usedin the processing. In many instances, human intervention is necessary todetermine the exact nature and validity of each trial solution. Further,certain data employed in the processing may be qualitative in form andtherefore not readily capable of being handled by the computer. Suchqualitative data is often too complex to integrate, as a practicalmatter, into automatic procedures and therefore must be considered by anoperator.

To date, the computer art has developed to an extent where processingspeeds of computer systems are not limited by the computer itself butrather by the input and output equipment utilized. In order to permitoptimum use of the computers extensive capabilities, it is desirable toutilize the minimum amount of input/output hardware which permitsefficient use of the maximum amount of computer capabilities. In orderto reduce the total re- 3,158,317 Patented Nov. 24, 1964 sponse timesdiscussed above, it is desirable to eliminate time consuming portions ofthe usual operational chain pointed out and particularly that portion ofthe chain which necessitates that the requester communicate with acomputer system by Way of a programmer.

In the complexities of modern business, varied and unrelated problemsoften arise to whose solution a computer may contribute to anappreciable extent. For example, an executive of a large chain store maybe interested in obtaining detailed data with respect to the saleshistory of a particular item. A completely um related problem may haveto be solved by the stores inventory manager with respect to preventinventory levels and their relationship with anticipated sales. Anothersituation may involve the accountant who often has occasion toinvestigate various aspects of the stores payroll. It is apparent thatthe executive, the inventory manager and the accountant all areinvestigating essentially unrelated problems whose solutions, takentogether, are necessary to the proper functioning of the storeoperation. Although it is apparent that large-scale computer systems areeasily capable of storing, manipulating and re trieving sufficientinformation to facilitate analysis and solution of the complex andunrelated problems of each of the parties mentioned, the development of.appropriate input/ output equipment which permits eifcctive minimizationof the total response time from request to solution continues to benecessary. The present invention contributes to this development byautomatically associating the requester with the stored computer routineeffective in providing a solution to his problem.

In the light of the above, it is a general object of this invention toprovide a control device for facilitating communication between a humanoperator and an electronic apparatus.

It is a more particular object of this invention to provide aninput/output device which permits a human operator to directlycommunicate with an electronic computer without the necessity of aprogrammer independently coding the request made in the requesterslanguage.

It is a still more particular object of this invention to provide aninput/output device whose basic functions can be very easily and quicklymodified to suit the immediate purposes of a plurality of differentusers.

Briefly, the invention includes a keyboard comprising the computer inputdevice, a set of perforated sheets adapted to be individually installedon the keyboard as overlays and associated computer networks andequipment. Each overlay relates to a particular problem area andcorresponds to a routine stored in the computer equipment. Wheninstalled on the keyboard, the overlay actuates a combination ofswitches located under the keyboard, the combination being unique to theparticular overlay and comprising a code which is converted to signalstransmitted to the computer to effectuate a lookup sequence for thecorresponding address in its memory. The information in the address,when accessed, comprises the selected routine. Subsequent depression ofkeys of the keyboard causes the computer to perform subroutines(portions of the selected routine) corresponding to human languagelabels, on the overlay, adjacent the keys. A light is associated witheach key and each label and means are provided coupling the lights tothe output of the computer such that the computer controls theirillumination for indicating to an operator his previous action andsubsequent action options.

Each overlay may consist of thin sheet of a relatively tough plasticmaterial, such as a polyester, on which the labels may be printed. Theparticular combination of switches actuated is related to the presenceor absence of holes in the overlay. When the overlay is installed on thekeyboard with a relatively heavy transparent plate (compared to theweight of overlay) holding it down, those switches located where thereare no holes in the overlay are actuated, whereas those switches locatedwhere there are holes are not actuated. Thus each overlay bears its ownunique code.

Other objects and advantages will become subsequently apparent in thelight of the fuller description below, reference now being made to theaccompanying drawings forming a part hereof wherein like numerals referto like parts throughout, and in which:

FIGURE 1 is a perspective view showing the external configuration of aninput/output console in which the invention may be embodied;

FIGURE 2 is an enlarged fragmentary perspective view of the consolerequest keyboard of FIGURE 1 and an overlay sheet and holding plateadapted to be fitted in place over the keyboard;

FIGURES 2A and 2B are fragmentary sectional views taken on the lines2A2A and 2B--2B, respectively, of FIGURE 2 showing an unactuated switchand an actuated switch, respectively;

FIGURE 3 is a block diagram showing the over-all relationships betweenthe portions of the input/output console of FIGURE 1 and a computer towhich the con sole is connected;

FIGURE 4 is a diagram of a circuit associated with the keyboard ofFIGURE 2 for generating coded signals identifying the overlay sheets andrequest keys;

FIGURE 5 is a block diagram of a portion of the input circuits of FIGURE3;

FIGURE 6 is a diagram of the circuit of the end of message coder ofFIGURE 5',

FIGURE 7 is a graph representing an exemplary coded signal input to thecomputer of FIGURE 5;

FIGURE 8 is generic representation of a flip-flop K1 shown for thepurpose of explaining the terminology of the specification;

FIGURE 9 is an extract of the computer flow diagram relevant to thepresent invention;

FIGURE 10 is a schematic diagram of the light circuitry of the keyboardof FIGURE 2; and

FIGURE 11 is a more detailed showing of the circuitry used inconjunction with each light in FIGURE 10.

With continuing reference to the drawings, initial attention is calledto FIGURES 1 and 3 wherein are shown respectively a physical embodimentof a display console in which the features of the present invention maybe incorporated and a functional block diagram illustrating the mannerin which the console is utilized with a computer for problem analysis.The console of FIGURE 1 includes a housing 10 defining a front panel 12through which the face of a cathode ray tube 14 projects. A plurality ofindicators 16 also project through the panel 12 so as to be clearlyvisible to an operator sitting in front thereof. The housing 10 isprovided with a shelf or desk portion 18 (arranged so that the operatormay sit opposite the panel 12 with his knees beneath the shelf 18)carrying thereon keyboards 20, 22, and 24. The keyboards 20 and 22comprise respectively display control and alphanumeric input keys. Asindicated in FIGURE 3 (wherein the dotted rectangle represents thehousing 10), the keyboards and also overlay code switches 49 are capableof generating signals which are conveyed to an input circuit 26, andthen to a digital computer 28. The computer 28 is coupled through outputcircuits 30 and then through display circuits 32 and illuminator logic34 respectively to the cathode ray tube 14 and the lights associatedwith keyboard 24. The improvement herein principally concerns the useand attendant advantages of the request keyboard 24. The detailedshowing of request keyboard 24 offered in FIGURE 2 reveals a pluralityof request keys R1, R2, R3 R8, R9. Although the request keyboard 24 isshown to include only nine keys, it will be realized that the quantityof keys has been chosen for exemplary purposes only and a much greaternumber of keys could be utilized. Each of the request keys RIP-R9 istranslucent for the purpose of permitting the illumination of respectivelight sources LR1-LR9 disposed thcrebeneath to be visible through thekeys. The keys ill-R9 constitute switch actuators which, when depressed,actuate pulse type switches (FIGURE 4). Adjacent each of the keys R1-R9is a cavity C1 C9. Each of the cavities C1-C9 respectively has mountedtherein a light source LfZ-LC9. A sheet 38 is adapted to overlay the keboard 24 with the keys lil -R9 projecting through o wings in the sheetand with labeled translucent portions "Fl-T9 of the sheet disposedimmediately above the cavities C1-C9. The sheet 38 lies on a translucentplate 3? having openings through which the request keys R1-R9 project.The translucent portions Tl-T9 of the overlay Iii? have a crosssectional area identical to that of the avitics Cit-C9 so that whenplaced on the keyboard 24, each translucent portion will overlay andcover a cavity and also become associated by position with an adjacentrequest key. Human language indicia is inscribed on each of theranslucent portions T1T9 and thereby serves to label in human languagethe computer function that will be initiated by the depression of any ofrequest keys Ill-R9.

It has been pointed out that the invention involves a computer storing amultiplicity of diverse routines and provides a requester with improvedmeans with which to initiate subroutines in order to investigateparticular problem areas. In order for the computer to recognize theproblem area with which the requester is concerned and make availablethe appropriate routine corresponding thereto, a plurality of differentoverlay sheets 38 are provided, each sheet having identifying encodingmeans such as circular holes in its end portion 40 at locations designated 41-4-l. As shown by broken lines, there are no holes at locations41 and 43 but there are holes at locations 42 and 44. The locations atwhich holes exist serve to uniquely identify each overlay sheet 38. Itwill be appreciated that eight distinct code possibilities are providedwhen three holes are utilized, thereby permitting the use of eightoverlay sheets. (However, as will be seen below, one code possibility isused to represent an end of message code so actually in the embodimentillustrated only seven sheets may be used.)

When an overlay sheet 38 is installed over the keyboard 24, its holepositions 41-44 respectively overlie the positions of the actuators of aplurality of switches 45 48, which extend upwardly through the plate 39.The switches are collectively designated as 49. As shown, the actuatorsof switches 46 and 48 would extend through the overlay 38 at holelocations 42 and 44, respectively, but the actuators of switches 45 and47 would be engaged by the overlay at locations 41 and 43, respectively,where there are no holes in the overlay, as shown in FIGS. 28 and 2A,respectively.

The light-weight overlay 38 may be made of a thin, relativcly tough,translucent, plastic material, such as a polyester, on which the labelsidentifying the keys Rl-R9 may be printed. The overlay is maintained inposition on the keyboard 24 by a relatively heavy (compared to theoverlay) holding plate 50 having openings corresponding to the positionsof the keys Rl-R9. The holding plate 50 is transparent and both it andthe translucent plate 39 may conveniently be made of a methylmethacrylate material, such as those known commercially as Lucite andPlexiglas, approximately one-eighth inch thick.

The holding plate 50 is provided with a plurality of holes 51-54 whichextend part way through the plate from its underside (as seen in FIGS. 2and 2A) and correspond in location to the locations 41-44, respectively,in the overlay 38. The primary purpose of the holes 5154 in the plate 50is to ensure that the plate does not engage any of the actuators of theswitches 4548 that may extend upwardly through holes in the overlay 38.It is pointed out that the holes 51-54 in the plate 50 are made onlyslightly larger than the actuators of the switches -48. This preventsthe actuators from pushing the overlay 38 up into the holes 51-54 inthose locations where there are no holes in the overlay, and permits theuse of thin, rela tive flexible, inexpensive overlays. The plate may behinged, if desired, and spring loaded to keep it down against thekeyboard or other conventional means such as latches used for thatpurpose.

The arrangement shown in FIG. 2 of four switches 45-48 and correspondinghole locations in the overlay 38 and the plate 50 is shown for purposesof illustration only. In practice, any desired number may be utilized,depend ing on the number of computer routines from which a selection isto be made. It is thus possible to have a large number of different,inexpensive overlays 38 and only one of the more expensive holdingplates 50.

It is particularly pointed out that no overlay 38 has a hole at location41. This insures that the switch 45, hereafter referred to as theoverlay switch, is actuated when ever an overlay is in position, alongwith such switches 46-48 as are actuated to identify the particularoverlay.

Although the switches 4548 have been described as having normally opencontacts which are closed when there is no corresponding opening in theoverlay 38, it is apparent that the switches 46, 47, 48 could havenormally closed contacts which are opened when there is no correspondingopening in the overlay. In that case, of course, the coding of thevarious overlays would be complementary to that used with normally-opencontact switches. It is preferred that the overlay switch 45 be of thenormally-open contact type, so that the presence of an overlay in placeon the keyboard will close its contacts.

Attention is now called to FIGURE 4 wherein is shown the circuitarrangement used to generate coded signals initiated by actuation of thekeys and switches associated with keyboard 24. It will be noted thatkeys R8 and R9 serve merely as spares and are not connected in thecircuit. Keys R2-R6 are each actuators of normally open single poleswitches. Key R1 is an actuator of a double pole switch, both switchsegments being normally open.

Key R7 is the actuator of a make before break double pole switch inwhich the normally open upper switch segment operates prior to thenormally closed lower switch segment. All of the switches actuated bykeys R1-R7 are of the pulse type Such that they only momentarily closeor open as the case may be, regardless of how long the keys aredepressed.

A battery is connected at a first terminal to ground.Previously-mentioned overlay switch 45 is connected between the secondbattery terminal (which will hereinafter be referred to as the highvoltage level with ground being referred to as the low voltage level)and junction 62. The upper switch segment associated with key R1 is connected on a first side to junction 62 and on a second side to signaturelines No. 1 and No. 2 through diodes 64 and 66 respectively and to datalines No. 1, No. 2 and No. 3 through diodes 68, 70 and 72, connectedrespectively in series with previously mentioned overlay identificationswitches 46, 47 and 48, respectively. The lower switch segmentassociated with key R1 is connected between junction 62 and conductor 74which in turn is connec ed to ground through the normally closed lowerswitch segment associated with key R7 and coil 76 of relay 78.

Relay 78 operates ganged switch segment 80, which is normally open andsegments 82 and 84 which are normally closed. Switch segment serves as aholding switch to maintain relay 78 energized after the lower switchsegment associated with key R1 has closed and opened. Switch segment 82serves to operate indicator light 86 (among indicators 16 on housing 10)which remains illuminated at all times except after an overlay sheet 33has been placed over keyboard 24 to close switch 45, and key R1 has beendepressed. The effect of the light 86 being off is to advise an operatorthat an overlay code has been generated and transmitted to the computerand 6 that request keys R2-R7 may now be depressed. Switch segment 84serves to control the key lights LRl-LR9 and the label lights LC1LC9 bydisabling them when relay 73 is not energized, in a manner to be morethoroughly discussed below.

Each of the switches associated with keys R2-R6 and the upper switchsegment associated with key R7 is connected between conductor 74 andsignature line No. 2 through diodes 88, 90, 92, 94, 96, 98 respectively.Diode 100 connects the switch associated with key R2 to data line No. 1.Diodes 102, 104, 106, 108, 110, 112, 114 and 116 connect the switchesassociated with keys Fill-R7 to the data lines so that each switch iscapable of generating a unique signal on the data lines.

With an overlay sheet 38 in place over the keyboard 24, switch 45 willbe closed and such switches of switches 41?, 47, 48 as are necessary toidentify the particular sheet will be closed. When key R1 is depressed,a high voltage pulse will be applied to signature lines No. 1 and No. 2and such of the data lines as are connected to closed switches ofswitches 46, 47, 48. Also, relay 78 will be energized and a high voltagelevel will be applied to conductor 74. When any of keys R2-R6 are thendepressed, a high voltage pulse will be applied to signature line No. 2and only certain data lines. For example, depression of key R3 causes ahigh voltage pulse to be applied to data line No. 2. Depression of keyR7 causes the normally upper switch segment associated therewith toclose before the normally closed lower switch segment opens so that highvoltage pulses are applied to signature line No. 2 and data lines No. 2and No. 3 before the high voltage level is removed from conductor 74.

It will therefore be appreciated that the circuit arrangement of FIGURE4 performs the function of generating coded signals on data lines No. 1,No. 2 and No. 3 identifying the overlay sheet 38 in place. These codedsignals, in a manner to be described, are sent to the computer 28 andinitiate operations which cause a stored routine, corresponding to theproblem area designated by the human language labels on the overlay, tobe deposited in an active file. The circuit arrangement of FIG- URE 4 inaddition performs the function of generating coded signals identifying aparticular request key R2- R7 that has been depressed. These codedsignals, in a manner to be described, are sent to the computer 28 andinitiate the performance of subroutines of the routine in the activefile, the subroutines corresponding to the request designated by thehuman language on the translucent sheet portion T2T7 adjacent therequest key to which the signals correspond.

Attention is now called to FIGURE 5 wherein is shown a block diagramillustrating the arrangement employed to couple the coded signalsgenerated by the circuit arrangement of FIGURE 4 to the computer 28. Theblocks of FIGURE 5 represent a more detailed showing of the elementsnecessary to the input circuits" block 26 of FIGURE 3. In addition tothe blocks shown in FIGURE 5, the input circuits" may includeappropriate buffer equipment, if needed, to compensate for inequalitiesin speed between computer operation and the rate at which inputinformation can be generated. Inasmuch as it is desirable to reduce thenecessary number of conductors connecting the input circuits 26 to thecomputer 28, a preferred means of transmission is to send the necessarysignals sequentially rather than simultaneously. Accordingly, circuitsare arranged as shown in FIGURE 5 for initially sending the signaturecode and thereafter the data code.

In addition to the three signature lines and the three data linesextending from the circuit of FIGURE 4, conductor 118, connected tosignature line No. 2 extends therefrom. From the foregoing discussion ofFIGURE 4, it should be realized that a high voltage pulse on bothsignature lines No. 1 and No. 2 indicates that the signal on the datalines identifies a particular overlay sheet 38.

On the other hand, a high level voltage pulse on only signature line No.2 indicates that the signal on the data lines identifies a particularkey. It is apparent therefore that regardless of what code is beinggenerated, a high voltage pulse will appear on signature line No. 2.Accordingly, conductor 118 is connected as one input to ready logiccircuitry 120 together with conductor 122 which extends from thecomputer 28. At certain times the computer 28 may not be ready to acceptinformation and at these times a flip-flop F1 (not shown) will be falseso that a low voltage level appears on conductor 122 connected to theoutput of the flip-flop. When the input lines 118 and 122 to the readylogic circuitry 120 are respectively high and low, a not ready light 121(among indicators 16 on housing is energized to advise the operator thathis input has not been transmitted to the computer. On the other hand,if conductor 1125 is high when conductor 122 is high, the ready logiccircuitry impresses a high voltage level on conductor 124.

An input register 126 including stage 1" 132 and stage 2" 134, eachhaving three flip-flops, is provided to store the signature signals anddata signals respectively. The signature and data lines are connected tothe appropr ate stages of the input register 126 through inhibit logic1" gate 128 and inhibit logic 2 gate 130 respectively. The gates 128 and131) are controlled by the level on conductor 124 such that thesignature and data signals are transferred to the input register 126only if conductor 124 is high. The ready logic circuitry 120, theinhibit logic 1 gate 128, and the inhibit logic 2 gate 130 may all beformed of conventional and, or," etc.

gates.

A clock 135 which provides a recurring square wave pulse and conductor124 form inputs to an an gate 136 whose output is fed to counter" 138.Counter lines 140, 142 and 144 which are pulsed sequentially. Line isconnected as an input to input logic gate 146 together with the threeoutput lines from stage 1 132 and when line 140 is pulsed the signalsstored in stage l 132 are fed out to computer 28. Line 142 is connectedas an input to shift logic gate 148 together with the three output linesfrom stage 2" 134 and when line 142 is pulsed, the signals stored instage 2 134 are shifted into stage 1 132. Line 144 is connected as aninput to cycle counter 150 and stage 2 134. Cycle counter 150 andcounter 138 may be identically constructed, it being necessary for eachto count sequentially to three. Cycle counter 150 has three output lines151, 152 and 153 but only line 152 is utilized. Each time line 144 ispulsed. meaning that counter" 138 has completed a cycle, cycle counter150 counts so that after the first cycle of counter 138, line 151 ispulsed, after the second cycle line 152 is pulsed, and after the thirdcycle line 153 is pulsed. When the keys R1R7 of FIGURE 2 are depressed,the switches of FIGURE 4 are actuated and signature and data signals areread into stage 1 132 and stage 2 134 respectively and operation ofcounter 138 is initiated.

In the first cycle of counter 138, the sequential pulses on lines 140,142 and 144 respectively cause the signature signals to be fed out ofstage 1 132 to the computer, the data signals to be shifted from stage 2134 to stage 1 132, to clear stage 2" 134 and the cycle counter 150 topulse line 151, In the second cycle of counter 138, the sequentialpulses on lines 140, 142 and 144 respectively cause the data signals(now in stage 1 132) to be fed out to the computer, the cleared contentsof stage 2 134 to be shifted into stage 1 132 and the cycle counter 138to pulse line 152 connected to EOM coder 156 to cause the end of messagecode to be generated and stored in stage 1" 132. Referring momentarilyto the details of the EOM coder 156 in FIGURE 6, it will be noted thatthe end of message code constitotes three high level pulses which itwill be recalled 138 has three output represents the code which has notbeen used to represent either signature or data signals. In the thirdcycle of counter 138, the end of message code (now in stage 1" 132) isfed out to the computer 28, the cleared contents of stage 2 134 areshifted into stage 1 132 and the cycle counter 150 pulses line 153. Aswill be more fully appreciated below in connection with the discussionof FIGURE 9, the operation of the equipment of FIG- URE 5 ceases as therecognition of the end of message code by the computer 28 sets flip-flopF1 (not shown) false so as to cause conductor 122 to fall to a low levelthereby causing line 124 to fall to thereby prevent counter 138 fromcounting further.

Attention is now called to FIGURE 7 wherein the relationship between anexemplary output from input logic" 146 and the output of clock 135 isillustrated. It has been assumed that key R1 has been depressed and thata particular overlay sheet 38 having no hole at location 43 has beenplaced over the keyboard 24. During the first cycle of counter 138pulses are applied to input logic" output lines No. 1 and No. 2 at thefirst clock pulse representing an overlay signature and indicating thatthe data following is associated with a particular overlay sheet 38rather than one of the keys ill-R9. During the second cycle, only lineNo. 2 is pulsed meaning that overlay No. 2 (assuming a binary code) isin place over keyboard 24, which actuates the switch 47. During thethird cycle, lines 1, 2 and 3 are pulsed representing the end of messagecode. By recognizing the data representing the overlay in place onkeyboard 24, the computer 28 is able to perform operations consistentwith the human language labels on the sheet.

Reference is now made to FIGURE 9 with momentary attention being paid toFIGURE 8 for the purpose of introducing the reader to the nomenclatureused in the flow diagram of FIGURE 9 depicting a portion of theoperation of computer 28. In order to explain the operation of computer28, logical equations representing the operations occurring in each wordperiod are shown in FIG- URE 9 beneath a numbered block. Each of thenumbered blocks represents a different state of a state counter (notshown). This system of computer sequencing is well known in the art andneed not be discussed other than to point out that the state countertends to increase its count in an orderly fashion as the one-word periodoperations are sequenced from left to right on the flow diagram,However, a control flip-flop K1 is provided for control so that thestate counter can be forced to stick," that is keep the same count forseveral word periods or skip, that is deviate from the orderly countingfashion. A counter (not shown) fed by a recurring clock signal providesthe input signal at the end of each word period to cause the statecounter to change state. The control fiipdlop K1 serves to control thestate to which the state counter changes. The control flip-flop K1 iscapable of being in either of two discrete states; that is either trueor false or correspondingly storing a "1 or "G." The system is definedsuch that the state counter will count in an orderly fashion at the endof each word period as long as the control flip-flop K1 is false butthat it will either stick" or skip if the control flip-flop K1 is true.Referring to the blocks of FIGURE 9, it will be seen that horizontal andvertical lines extend from the right side of the blocks. If the controlflip-flop K1 is false at the end of a word period, the state counterincreases its count by one, and follows the horizontal line as cg. fromstate block 3 to state block 4. If on the other hand, the controlflip-flop K1 is true at the end of a word period, the state counterfollows the vertical line and sticks or skips, as eg. from state block 2to state block 8. The discrete states of the slate counter aresignificant because in each state only those circuits necessary to causethe operations described by the logical equations under the state blocksare rendered operative. A brief description of the computer operationsin the various states is set forth in each state block.

A generic representation of a flip-flop is offered in FIGURE 8 for thepurpose of introducing the nomenclature used in FIGURE 9. Flip-flop K1in FIGURE 8 has two inputs and two complementary outputs. When outputline K1 is high, output line K is low and the flip-flop is said to betrue or storing a digit 1. On the other hand, when output line K is low,output line K is high and the fiip-fiop is said to be false or storing adigit 0. Whereas the flip-flop outputs are designated by upper caseletters, the inputs to the flip-flop are designated by correspondinglower case letters with a subscript (e.g. K prcfixing the input whichwhen triggered, causes the flip-flop to become false and the subscript 1(e.g. K prefixing the input which, when tri ered, causes the flip-flopto become true. The inputs to the flip-flop are controlled by gateswhich perform logical functions in the presence of computer clockpulses.

With the above explanation thought sufiicient to enable an understandingof the computer flow diagram, attention is now directed to FIGURE 9which depicts the operations performed by the computer. Broadly, theoperations include initially recognizing an end of message code so as tocause a low level to be applied to conductor 122 (FIGURE 5) and thendetermining whether the signature signals are representative of anoverlay or a key. If overlay signature signals are presented, theaccompanying data signals are compared with the ad dress of a routinepresently stored in an active file. If the comparison reveals that thedata signals correspond to the routine already in the active file,nothing further need be done and the computer returns to its idle state.If, on the other hand, the comparison does not reveal correspondence,the total routine library must be searched for the routine correspondingto the accompanying data signals and the located routine must then bewritten into the active file before the computer returns to its idlestate. If the signature signals were representative of a key. thecomputer would utilize the accompanying data signals to locate thesubroutine in the routine in the active file to which it corresponds andthen perform the subroutine prior to returning to its idle state.

The output signals from the input logic 146 (FIG- URE 5) are held in atemporary register (not shown), which will be referred to as the Bregister, which includes flip-flops BIB9. The signature signals whichare outputted during the first cycle of counter 138 (FIGURE 5) will beheld in flip-flops ill-B3, the data signals in flipfiops i34-B6 and theend of 137-89. The computer in state I is in an idle condition and sinceflip-flop K] has been preset true, sticks in state 1 until the end of aword period in which the end of message code is read into flip-flopsB7-B9. As expressed by the logic equation k Bq gBg, flip-flop K1 is setfalse by the end of message code and the computer enters state 2. Theend of message code also sets flip-flop R1 false so that a low voltagelevel appears on conductor 22 (FIGURE 5).

In state 2 flip-flop B1 is looked at to determine whether the signatureis representative of an overlay or a key, it being recalled from FIGURE4 that the overlay signature is characterized by a "1 in its firstposition while the key signature is characterized by a 0. If flip-flopB1 is false, control flip-flop K1 is set true and the state counterskips to state 8. If flip-flop B1 is true, the computer enters state 3.

In state 3, flipfiops E4-E6 of an E register (not shown) are used tocompare for equality between flipflops S4S6 of an S register (not shown)in which the address of the routine presently stored in an active file(not shown) is stored. As expressed by the logical equations beneathstate block 3, ilipflops E4-E6 are all set false if equality does existmeaning that the desired routine is already in the active file.

message code in flip-flops In state 4, control flip-flop K1 is set trueif flip-flops E4E6 are all false and the computer thereby enters state7. 0n the other hand, if flip-flops E4-E6 are not all false, thecomputer proceeds to state 5.

In state 5, the data stored in flip-flops B4-B6 is written intoflip-flops 84-56.

In state 6, the total routine library (not shown) is searched to locatethe routine having the address corresponding to the address stored inflip-flops 84-86 and the located routine is then written into the activefile (not shown) and the computer enters state 7.

In state 8, which the computer could enter after state 2, the routine inthe active file is searched for the subroutine whose address correspondsto the data and the located subroutine is performed and the computerthen enters state 7.

In state 7, flip-flops Fl, K1 and E4-E6 are set true and the computerenters state 1.

In summary, the computer serves to distinguish between overlay and keysignatures, uses overlay data to compare the requested routine with theroutine already in the active file and writes a new routine in theactive file if necessary or uses key data to initiate the performance ofa subroutine. Performance of the subroutine generally provides outputdata in the form of displays which are immediately presented to theoperator on cathode ray tube 14.

Depending on the output presented to the operator, the operator may Wantto investigate the problem further by, e.g., modifying data toinvestigate hypothetical situations, or merely looking at the presenteddata in more detail or in a different context. In problem analysis, itis often desirable to follow certain prescribed sequences. Also, it issometimes impossible for the computer to perform certain requests untilcertain data is supplied by the operator and the operator may be unableto supply this necessary data until be partially investigates the prob1611]. In order to lead the operator through a possibly complexprocessing chain, the previously mentioned light sources LC1.C9 andLR1-LR9 are provided beneath the labeled translucent sheet portions T1T9and translucent keys Rl-R9 respectively.

Writing a routine in the active file or performance of a subroutinecauses appropriate data to be written into a circulating register 180(FIGURE 10) which may include e.g. a drum. The illuminator logic 34(FIGURE 3) includes a matrix arrangement shown in FIGURE 10 controlledby the circulating register 180 and a word counter 182 to operate lightmemory units which are associated with each light source LCl-LC9 andLRl- LR9. The information in the circulating register is always modifiedafter one of the keys R1-R7 is depressed so that the light sourcebeneath the last key depressed will be illuminated to advise theoperator of his most recent action. Also, the light sources LCl-LC9 inthe cavities C1-C9 are selectively illuminated beneath the labeledtranslucent sheet portions to advise the operator of what requests hemay next logically make.

The light memory units 170 are shown in detail in FIGURE 11 and comprisea flip-flop L1 and an and gate 172. Conductor 174 connects switch 84(FIGURE 4) to the input of flip-flop L1 which causes the flip-flop L1 tostore a 0" whenever a high voltage level appears on conductor 174. Thelogical equation l =D where D represents the level on conductor 174shows that the light source connected to flip-flop L1 is prevented frombecoming illuminated as long as switch 84 is closed. The logicalequation I =DWA where A" represents the circulating register and W theword counter, shows that the flip-flop L1 is caused to store a "1 toilluminate the connected light source whenever the level on conductor174 is not high and the lines from the word counter and circulatingregister are both high.

From the foregoing, it should be appreciated that the invention hereinprovides means which enable an operator, unskilled in computer languageand techniques, to communicate with a computer in the language of theoperators are which is set forth as labels on the described overlaysheets. Moreover, the invention includes means so that by virtue of theremovable overlays, its functions can be rapidly changed so as tofacilitate the solution of many diverse problems requiring jointhuman-computer effort, the invention being characterized by an inputsection including keys used by the operator to send messages to thecomputer and an output section including lights controlled by thecomputer for directing the operator through complex problem analysis.

Although the device of the invention has been described in connectionwith a computer having routines and subroutines stored therein, it isapparent that it is not limited to use with a computer. For example, asa subcombination, the device may be used as a control or input devicewith the overlay acting to select any one or more of a plurality ofprimary electrical circuits and the keyboard acting to select secondarycircuits from the primary circuits.

The foregoing is considered as illustrative only of the principles ofthe invention. Since numerous modifications will readily occur topersons skilled in the art, it is not desired to limit the invention tothe exact construction and operation shown and described and accordinglyall suitable modifications and equivalents are intended to fall withinthe scope of the invention as claimed.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In combination with a computer storing a plurality of routines, inwhich each routine may include a plurality of subroutines, a devicecoupled to the computer and including first means for dispatching acoded message to the computer identifiable with a particular routine,and

second means for dispatching coded messages to the computer identifiablewith particular subroutines in any routine,

said second means including a plurality of subroutine actuating keys,

said first means including a sheet having at least one opening forselectively preventing actuation of switch means by said sheet togenerate a code identifiable with a particular routine,

said sheet being receivable over said keys with said keys projectingthrough second openings, and

labels on said sheet adjacent each of said second openings forindicating the subroutine corresponding to each key.

2. The combination of claim 1 including light sources associated witheach of said keys and each of said labels, and

computer controlled means connected to said light sources for effectingthe selective illumination thereof.

3. The combination of claim 1 wherein said device further includes afirst set of light sources and a second set of light sources,

each light source of said first set associated with one of said labelswhen said sheet is properly positioned over said keys,

each light source of said second set associated with one of said keys,and

third means coupling said light sources to the output of said computerfor selectively illuminating said light sources in response to computercontrolled messages.

4. In combination with a computer storing a plurality of routines eachof which may include a plurality of subroutines, a device connected tothe computer input for initiating computer operations comprising:

a keyboard including a plurality of subroutines actuating keys,

sheet means providing a set of labels for labeling each of said keysaccording to the subroutine it initiates,

said sheet means having openings therein for selectively preventingactuation of switch means for generating a signal identifying said setof labels, and means operatively connected to each of said keys forgenerating a key identification signal in response to actuation of aparticular key.

S. In combination with a computer storing a plurality of routines eachof which may include a plurality of subroutines, a device connected tothe computer input for initiating computer operations comprising:

a keyboard including a plurality of subroutine actuating keys,

sheet means providing a set of labels for labeling each of said keysaccording to the subroutine it initiates, said sheet means havingopenings therein for selectively preventing actuation of switch meansfor generating a signal identifying said set of labels,

second means operatively connected to each of said keys for generating akey identification signal in response to actuation of a particular key,and

third means preventing generation of said key identification signalprior to the generation of said signal identifying said set of labels.

6. In combination with a computer storing a plurality of routines eachof which may include a plurality of subroutines, a device for initiatingcomputer operations comprising:

a keyboard including a ing keys, sheet means providing a set of labelsfor labeling each of said keys according to the subroutine it initiates,

second means operatively connected to each of said keys for generating akey identification signal in response to actuation of a particular key,

said sheet means having labels thereon adapted to be received over saidkeyboard and having first openings therein with said keys projectiblethrough said first openings so that each key becomes associated byposition with one of said labels, and

a code generating circuit including a plurality of switches,

said sheet means selectively actuating said switches for identifyingsaid set of labels and having second openings therein for preventingactuation of selected switches.

7. In combination with a computer storing a plurality of routines eachof which may include a plurality of sub routines, a device forinitiating computer operations comprising:

a keyboard including a plurality of subroutine actuating keys, sheetmeans providing a set of labels for labeling each of said keys accordingto the subroutine it initiates,

second means operatively connected to each of said keys for generatingin response to actuation of a particular key, a key identificationsignal,

said sheet means having labels thereon adapted to be received over saidkeyboard and having first openings therein with said keys projectiblethrough said first openings so that each key becomes associated byposition with one of said labels,

a code generating circuit including a plurality of switches,

said sheet means selectively actuating said switches for identifyingsaid set of labels and having second openings therein for preventingactuation of selected switches, and

third means preventing generation of said key identification signalprior to operation of said switches.

8. An input device for use with a computer compris plurality ofsubroutine actuating:

a keyboard,

a sheet having labels thereon and first openings therein adapted tooverlay said keyboard with each of the 13 keys of said keyboardprojecting through said first openings and becoming associated byposition with one of said labels,

a code generating circuit including a plurality of switches,

means operatively connecting each of said keys to one of said switchessuch that actuation of a particular key operates a particular switch togenerate a code identifiable with said particular key, and

means acting on said sheet to cause said sheet to operate certain ofsaid switches for generating a code identifiable with said sheet,

said sheet having second openings for preventing operation of certain ofsaid switches. 9. In combination with a computer storing a plurality ofroutines, in which each routine may include a plurality of subroutines,a device coupled to the computer and including first means fordispatching a coded message to the computer identifiable with aparticular routine, and

second means for dispatching coded messages to the computer identifiablewith particular subroutines in any routine,

said second means including a plurality of subroutine actuating keys,

said first means including controllable coded-message generating means,

a sheet having means for actuating said generating means, and

holding means for holding said sheet in position for actuating saidgenerating means.

10. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, comprising:

keyboard means including a plurality of secondary function selectingkeys,

sheet means providing a set of labels for identifying each of saidselecting keys according to the second ary function it is adapted toselect, and

a plurality of primary function selecting means controllable by saidsheet means to select said primary functions,

said sheet means having at least one opening therein for selectivelypreventing actuation of at least one of said primary function selectingmeans by said sheet means.

11. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, compnsrng:

keyboard means including a plurality of secondary function selectingkeys,

sheet means providing a set of labels for identifying each of saidselecting keys according to the secondary function it is adapted toselect, and

a plurality of switch means actuatable by said sheet means to selectsaid primary functions,

said sheet means having at least one opening therein for selectivelypreventing actuation of at least one of said plurality of switch means.

12. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, comprising:

keyboard means including a plurality of secondary function selectingkeys,

sheet means providing a set of labels for identifying each of saidselecting keys according to the secondary function it is adapted toselect,

said sheet means having labels thereon adapted to be received over saidkeyboard means and having first openings therein with said keysprojectible through said first openings so that each key becomesassociated by position with one of said labels, and

a plurality of switches actuatable to select said primary functions,

said plurality of switches being located to be actuated by said sheetmeans when said sheet means is properly positioned on said keyboardmeans,

said sheet means having at least one second opening therein forselectively preventing actuation of at least one said switch forselecting a desired one of said primary functions.

13. The device defined by claim 12 further including means forpreventing selection of said secondary function until after said primaryfunction has been selected.

14. The device defined by claim 13, wherein said means for preventingselection of said secondary function includes a switch adapted to beactuated by said sheet means when properly positioned on said keyboardmeans.

15. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, comprising:

a keyboard including a plurality of secondary function selecting keys,

an overlay sheet for said keyboard having first openings therein withsaid keys projectible through said first openings, and

a plurality of primary function selecting means actuatable by saidoverlay sheet, when said overlay sheet is in place on said keyboard, toselect said primary functions,

said overlay sheet having at least one second opening therein forselectively preventing actuation of at least one of said primaryfunction selecting means by said overlay sheet.

16. The device defined by claim 15 further including means for holdingsaid overlay sheet on said keyboard in position to actuate said primaryfunction selecting means.

17. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, comprising:

a keyboard including a plurality of secondary function selecting keys,

a thin, relatively flexible overlay sheet for said keyboard providing aset of labels for labeling each of said selecting keys according to thesecondary function it is adapted to select,

said overlay sheet having first openings therein with said keysprojectible through said first openings,

a plurality of switches actuatable by said overlay sheet to select saidprimary functions,

said overlay sheet having at least one second opening therein forselectively preventing actuation of at least one of said plurality ofswitches, and

means for holding said overlay sheet on said keyboard in position toactuate said switches.

18. A control device for selecting at least one primary function from aplurality of primary functions and at least one secondary function froma plurality of secondary functions associated with each of said primaryfunctions, comprising:

a keyboard including a plurality of secondary function selecting keys,

a thin, relatively flexible, translucent overlay sheet for said keyboardproviding a set of labels for labeling each of said selecting keysaccording to the secondary function it is adapted to select,

said overlay sheet having labels thereon adapted to be received oversaid keyboard means and having first openings therein with said keysprojectible through said first openings so that each key becomesassociated by position with one of said labels, and

a plurality of switches actuatable to select said primary functions,

each of said plurality of switches having an actuator located to beactuated by said overlay sheet when properly positioned on said keyboardmeans,

said sheet means having at least one second opening therein forreceiving at least one of said actuators for selectively preventingactuation of at least one said switch for selecting a desired one ofsaid primary functions.

19. The device defined by claim 18 is further including means forholding said overlay sheet on said keyboard in position to actuate saidactuators.

20. The device defined by claim 18 further including a relatively rigidholding plate for holding said overlay sheet on said keyboard inposition to actuate said actuators,

said holding plates having openings thereinto receive any of saidactuators that project through said overlay sheet and prevent actuationthereof.

No references cited.

1. IN COMBINATION WITH A COMPUTER STORING A PLURALITY OF ROUTINES, INWHICH EACH ROUTINE MAY INCLUDE A PLURALITY OF SUBROUTINES, A DEVICECOUPLED TO THE COMPUTER AND INCLUDING FIRST MEANS FOR DISPATCHING ACODED MESSAGE TO THE COMPUTER IDENTIFIABLE WITH A PARTICULAR ROUTINE,AND SECOND MEANS FOR DISPATCHING CODED MESSAGES TO THE COMPUTERIDENTIFIABLE WITH PARTICULAR SUBROUTINES IN ANY ROUTINE, SAID SECONDMEANS INCLUDING A PLURALITY OF SUBROUTINE ACTUATING KEYS, SAID FIRSTMEANS INCLUDING A SHEET HAVING AT LEAST ONE OPENING FOR SELECTIVELYPREVENTING ACTUATION OF SWITCH MEANS BY SAID SHEET TO GENERATE A CODEIDENTIFIABLE WITH A PARTICULAR ROUTINE, SAID SHEET BEING RECEIVABLE OVERSAID KEYS WITH SAID KEYS PROJECTING THROUGH SECOND OPENINGS, AND LABELSON SAID SHEET ADJACENT EACH OF SAID SECOND OPENINGS FOR INDICATING THESUBROUTINE CORRESPONDING TO EACH KEY.